The invention concerns a rotor for use in screen graders having pulse and blade elements running in a screen basket. Such rotor is known from European Patent Document No. EP 0 404 624. The purpose of EP 0 404 624 is to impart a tangential or peripheral velocity to the suspension being graded which varies from the peripheral velocity of the impulse elements. According to such document, this is accomplished in that the radially outer edges of the blades are on a radius smaller than that of the impulse elements.